Flowserve 800 Piston Lift Check Valve - Manual (Page 4)

1.0 PHYSICAL DESCRIPTION AND OPERATION OF EQUIPMENT
1.1 Piston Check Valves (Figures 1 & 2 - See Section 11.0)
Piston Lift Check valves are generally used in applications where pressure drop
through the valve is not critical, although Flowserve piston check valves have a
relatively low pressure drop.
These small piston lift check valves include a return spring to facilitate closing.
All Flowserve piston check valves have body guided discs to provide resistance to
wear, thus, insuring a longer life. An equalizing hole is provided in the disc as a
drain for condensate in steam valves.
A dual seat may be supplied which provides a hard surface for high differential
pressure sealing and a resilient seat for sealing during low differential pressure.
These instructions are being furnished to the customer for use in the installation,
operation and maintenance of the 800 pressure class series piston lift check
valves.
2.0
DESIGN CONDITIONS
N/A
3.0
OPERATING CONDITIONS
N/A
4.0
TEST CONDITIONS
4.1 Each valve covered by this manual has received the following hydrostatic tests:
4.1.1 Shell hydrostatic test at 1.5 times the 100
°
F pressure rating.
4.1.2 A seat leakage and disc closure test at 110% of the 100
°
F pressure rating.